Question

I found this code that let´s me traverse through some xml elements:

$(somexml).find('company[id="'+id+'"] customers customer').each(function()
{
     var $tmp = $(this);
     alert($tmp.attr('customerid'));
});

seems to work pretty good. But since i´m novice at Javascript/Jquery i have some questions:

1. How can i respond to when the find() failed…no matches?

2. Why the ‘$’ before tmp? Why not just var tmp = $(this);

Answer 1

1: each returns the object it’s been called on, that is $(x).each returns $(x). So, assign the result of each to a variable and check its length:

var obj = $(somexml).find(whatever).each(function() {
    ...
});
if(!obj.length)
     nothing has been found...

2: $tmp instead of just tmp is a “hungarian” convention to denote jQuery objects. You are not required to use it.